BACKGROUND: The burden of hypertension and related health care needs among Mexican Americans will likely increase substantially in the near future.
Predictors of Hypertension Awareness, Treatment, and Control Among Mexican American Women and Men Andrea Bersamin, PhD1,2, Randall S. Stafford, MD, PhD1, and Marilyn A. Winkleby, PhD1 1
Stanford Prevention Research Center, Stanford University, Stanford, CA, USA; 2Center for Alaska Native Health Research, Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK, USA.
BACKGROUND: The burden of hypertension and related health care needs among Mexican Americans will likely increase substantially in the near future. OBJECTIVES: In a nationally representative sample of U.S. Mexican American adults we examined: 1) the full range of blood pressure categories, from normal to severe; 2) predictors of hypertension awareness, treatment and control and; 3) prevalence of comorbidities among those with hypertension. DESIGN: Cross-sectional analysis of pooled data from the National Health and Nutrition Examination Surveys (NHANES), 1999–2004. PARTICIPANTS: The group of participants encompassed 1,359 Mexican American women and 1,421 Mexican American men, aged 25–84 years, who underwent a standardized physical examination. MEASUREMENTS: Physiologic measures of blood pressure, body mass index, and diabetes. Questionnaire assessment of blood pressure awareness and treatment. RESULTS: Prevalence of Stage 1 hypertension was low and similar between women and men (∼10%). Among hypertensives, awareness and treatment were suboptimal, particularly among younger adults (65% unaware, 71% untreated) and those without health insurance (51% unaware, 62% untreated). Among treated hypertensives, control was suboptimal for 56%; of these, 23% had stage ≥2 hypertension. Clustering of CVD risk factors was common; among hypertensive adults, 51% of women and 55% of men were also overweight or obese; 24% of women and 23% of men had all three chronic conditionshypertension, overweight/obesity and diabetes. CONCLUSION: Management of hypertension in Mexican American adults fails at multiple critical points along an optimal treatment pathway. Tailored strategies to improve hypertension awareness, treatment and control rates must be a public health priority. KEY WORDS: Mexican American; hypertension; health care; practice patterns; secondary prevention. J Gen Intern Med 24(Suppl 3):521–7 DOI: 10.1007/s11606-009-1094-6 © Society of General Internal Medicine 2009
INTRODUCTION Hypertension is the most prevalent modifiable risk factor for cardiovascular disease (CVD) among U.S. adults (29%)1, surpassing the prevalence of smoking, obesity and diabetes.2 Although the benefits of blood pressure treatment and control on cardiac and cerebrovascular outcomes are well-established,3,4 more than one-third of U.S. adults who have been diagnosed with hypertension are untreated1 and two-thirds have inadequate blood pressure control.5 Racial/ethnic differences in hypertension prevalence, awareness, treatment and control are well documented 1,5–7. Of particular concern are the lower rates of blood pressure treatment and control that have consistently been observed among Mexican Americans than among non-Hispanic whites and African Americans. The burden of hypertension and related health care needs among Mexican Americans are likely to increase in the near future for several reasons. First, the Hispanic population, the large majority of whom is Mexican American, is the fastest growing ethnic minority population in the United States and is expected to grow 188% between 2000 and 2050 8 . The numbers of older Mexican Americans are growing particularly fast9; it is this age group that has the highest burden of hypertension10 and is most likely to need health care for hypertension-related complications. Second, Mexican Americans are disproportionately uninsured (49% of foreign-born Mexican Americans and 21% of U.S. born Mexican Americans are uninsured)11 so they are less likely to receive preventive treatment. Finally, Mexican Americans are more likely to be overweight12–14 and have diabetes15 than non-Hispanic whites. Patients with such comorbidities constitute a large percentage of patients treated for cardiovascular and other chronic diseases.16 Most epidemiological studies of hypertension among Mexican Americans have been descriptive, estimating hypertension prevalence, awareness, treatment and control.6 Few studies have examined correlates of hypertension awareness, treatment and control7,17,18, knowledge that is critical to identifying and appropriately treating higher risk subgroups. Furthermore, almost all previous studies have focused on only two categories of blood pressure status- normotensives and hypertensives, without further examining a range of hypertension categories that includes prehypertensives as well as stage 1 and stage 2 hypertensives. This further examination can provide important and more refined indicators of hypertension control and indicators of the effectiveness of clinical and public health efforts. Lastly, to our knowledge, few or no national studies have examined the prevalence of comorbidities among hypertensive Mexican Americans that can contribute an S521
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Bersamin et al.: Predictors of Hypertension Management in Mexican American Adults
additional dimension to their cardiovascular disease risk profile. The following are therefore the objectives of this paper: 1) to examine the full range of blood pressure categories, from normal to severe among Mexican American women and men using pooled data from a national U.S. sample of NHANES, 1999–2004; 2) to examine correlates of hypertension awareness, treatment and control and; 3) to estimate the prevalence of comorbidities among those with hypertension. Our objective is to better define the processes that contribute to poor blood pressure control among Mexican American patients; Mexican American subgroups most in need of clinical and public health interventions; and, the level of cardiovascular disease risk among Mexican Americans.
METHODS Sample Data are from the 1999–2004 National Health and Nutrition Examination Surveys (NHANES), a nationally representative sample of the civilian, non-institutionalized U.S. population that uses a stratified multistage probability design and oversamples Mexican Americans. Our study sample included nonpregnant Mexican American adults (aged 25–84 years) who underwent a standardized physical examination. The overall response rates for the physical examination was 77% (rates are unavailable for specific ethnic groups).19
Ethnicity NHANES respondents were asked to classify their race/ ethnicity as black; Mexican or Mexican American; white; Asian or Pacific Islander; Aleut, Eskimo or American Indian; or other Latin-American or other Spanish. Adults who selected Mexican or Mexican-American were included in our analyses.
Primary Outcome Hypertension status, awareness, treatment, and control were the primary outcomes and were defined in accordance with the Joint National Committee on Prevention, Evaluation, and Treatment of High Blood Pressure.20 Prehypertension was defined as systolic blood pressure (SBP) 120–139 mm Hg or diastolic blood pressure (DBP) 80–89 mm Hg. Hypertension was defined as SBP≥140 mm Hg or DBP≥90 mm Hg or on antihypertensive medications. Individuals with hypertension were further classified as having Stage 1 hypertension (SBP 140–159 or DBP 90–99) or Stage ≥2 hypertension (SBP≥160 or DBP≥100). We report the mean of the second and third of three blood pressure readings, measured on the right arm by a physician while the participant was seated during the medical examination. Hypertensive individuals who responded positively to the question, “Have you ever been told you had hypertension?” were classified as aware. Hypertensive individuals who responded positively to the question, “Because of your high blood pressure are you now taking prescribed medication?” were classified as being treated for hypertension. Treated individuals whose SBP was
